The Lava Eel is a fish that can be caught during all times and seasons in The Mines on the 100th floor and at the Forge at the top of the Volcano Dungeon. It is the only fish that can spawn in lava. It spawns rarely in The Mines and much more commonly at the Forge.
Lava Eels can be placed in a Fish Pond, where they will reproduce every 5 days. The initial pond capacity is 1 fish, but the capacity can be increased to 10 by completing four quests. After the first quest is completed, the color of the pond water changes to red. The primary output is red Lava Eel Roe, but Gold Ore is possible starting at population 3 and several more valuable items are possible starting at population 9.